Integrating Natura2000 into critical load calculations for nitrogen
Tamis, W.L.M.; Bakker, N.V.J. de; Zelfde, M. van 't
Citation
Tamis, W. L. M., Bakker, N. V. J. de, & Zelfde, M. van 't. (2008). Integrating Natura2000 into critical load calculations for nitrogen. Leiden: CML Department of Environmental Biology (oud --> CML-CB). Retrieved from https://hdl.handle.net/1887/13200
Version: Not Applicable (or Unknown)
License: Leiden University Non-exclusive license
Integrating Natura2000 into critical load calculations for nitrogen
W.L.M. Tamis N.V.J. de Bakker M. van ’t Zelfde
August 2008
CML technical report 44
Department of Environmental Biology
CML
Institute of Environmental Sciences
Integrating Natura2000 into critical load calculations for nitrogen
W.L.M. Tamis N.V.J. de Bakker M. van ’t Zelfde
August 2008
CML technical report 44
Department of Environmental Biology
Electronic copies of the report can be downloaded from the Publications section of the Department of Environmental Biology website at:
http://www.leidenuniv.nl/cml/sem/publications/index.html
A hard copy of the report can be borrowed on request by contacting the CML library at:
eroos@cml.leidenuniv.nl
Contents ...iii
Preface ...iv
Summary ... v
Samenvatting ...vi
1. Introduction... 1
1.1. Nature protection in Europe: Natura2000 ... 1
1.2. Nitrogen deposition ... 1
1.3. Calculations of critical loads for Natura2000 areas ... 2
1.4. Aim of the project ... 2
2. Basic data of Natura2000... 5
2.1. General... 5
2.2. Description of the Natura2000 data... 5
2.3. Conversion of spatial information of Natura2000 areas ... 7
3. Biodiversity in Natura2000 areas in relation to critical load analysis ... 11
3.1. General introduction ... 11
3.2. Nitrogen enrichment effects on fauna ... 11
3.3. When and how apply critical load analysis in Natura2000 areas? ... 12
3.4. Conversion from Palearctic to EUNIS habitat types ... 17
3.5 Coupling of empirical critical loads to Natura2000 areas ... 19
3.6. Changes in biodiversity in Natura2000 areas ... 19
4. Production of eCL-maps for Natura2000 areas ... 21
4.1. General... 21
4.2. Handling of habitat information and assignment of eCL for Natura2000 areas.... 21
4.3. Production of the eCL-maps for Natura2000 areas ... 24
5. Discussion and recommendations ... 27
5.1. Information and production of eCL-maps for Natura2000 areas ... 27
5.2. Integration of Natura2000 areas into the critical load analysis ... 28
References ... 31
Annex 1 Flowcharts of data handling for Natura2000 areas ... 33
Annex 2 Overview of directories and files in Natura2000 folder ... 38
Preface
The Coordination Centre for Effects (CCE) located at MNP, commissioned the Institute of Environmental Sciences, Leiden University (CML) to integrate the Natura2000 into the critical load calculations for nitrogen. The research includes the necessary basic steps of collection, description, assemblage, conversion of Natura2000-information and adaptation of critical load procedures to include this information. Results of this study were presented at the CCE-workshop (Sofia, 23-25 April 2007). The research had been carried out by Nancy de Bakker (Chapter 1, partially 2, and 3) and Maarten van ’t Zelfde (Chapter 2 and 4) under supervision of Wil Tamis (Chapter 5 and redaction) at CML, and Jaap Slootweg and Jean-Paul Hettelingh at CCE. Arjan van Hinsberg (MNP) is gratefully acknowledged for the discussions about impact indicators for nitrogen deposition for biodiversity in the SEBI-project.
Wil Tamis
Leiden, July 2008
Summary
The Coordination Centre for Effects (CCE) develops modelling and mapping methodologies on European critical loads. This includes collaboration with 27 National Focal Centres in Europe on critical loads and related variables. CCE deliverables become available for integrated assessment models used for the support of air pollution policies under the LRTAP-Convention and the European Commission.
One of the main aims of air pollution control policies is the protection of biodiversity by providing good environmental quality. Therefore, biodiversity, especially at the European scale, should play a more pronounced role in critical load analysis. CCE commissioned the Institute of Environmental Sciences of Leiden University (CML) to integrate Natura2000 areas, one of the main instruments to protect biodiversity in Europe, into the critical load calculations for nitrogen. The general aim of this technical project was to collect information of Natura2000 areas, both on geography and biodiversity, and develop procedures to apply and interpret this biodiversity information in calculations of critical loads for nitrogen.
Information of Natura2000 areas was collected and described, regarding spatial (geographical position) and attribute data (status, habitats, biodiversity, threats etc.). This information was aggregated and converted to make further processing in the critical load calculations for nitrogen possible. This includes the selection of information of the Natura2000 areas and of combining information of Habitat- and Bird-directive per Natura2000 area, the conversion of geographical codes and eventually the overlay with the EMEP50-grid.
It is further investigated whether and how the different Natura2000 areas and species can be included in the critical load analysis by using a ‘habitat-approach’. A procedure was developed to establish whether a critical load calculation for nitrogen is necessary for a particular N2000 area, e.g. for an area used as wintering ground for birds no critical load analysis is needed. It is concluded that for species mentioned in the Habitat and Bird Directive habitat-information is lacking at the moment. The conversion of the habitat classification used for Natura2000 areas to the EUNIS habitat classification used in the critical load analysis is described. With these EUNIS habitat classes a coupling with empirical critical loads (eCL) is possible. Also the need and possibilities to include changes in biodiversity in critical load analysis was explored.
Based on former information and procedures the production in several steps of the critical load maps is described. Several variants of eCL-maps for Natura2000 areas are presented and compared among each other and with the eCL-map for all ecosystems (non- Natura2000 ánd Natura2000 areas) from the SEI-map. Depending on the variant Natura2000 areas are more sensitive than non-Natura2000 areas, with exception of Scandinavian and mountainous regions. The results are dependent of the kind of habitat information included in the analysis.
A large number of discussion points and recommendations are mentioned. These are focused on the one hand on the improvement of the available data on Natura2000 areas and eCL. On the other hand these are focused on the improvement of the procedures to perform critical load analyses and to produce critical load maps, especially with attention to which kind of habitat information to include in the map for the critical load analysis.
Samenvatting
Het Coordination Centre for Effects (CCE) van het MNP ontwikkelt modellen voor de bepaling van kritische drempels [Eng.: critical load(s), afk. CL] voor atmosferische depositie. Voor dat doel werkt het CCE nauw samen met 27 National Focal Centres in Europa met betrekking tot deze kritische drempels (CL). De producten van CCE ondersteunen het internationale (LRTAP) en Europese beleid ter bestrijding van luchtverontreiniging. Een van de hoofddoelen van het beleid ter bestrijding van luchtverontreiniging is de bescherming van de biodiversiteit door het verzorgen van een goede milieukwaliteit. Hiervoor zou biodiversiteit op Europese schaal een meer centrale rol moeten spelen in de CL analyse. CCE heeft het Centrum voor Milieuwetenschappen van de Universiteit Leiden (CML) de opdracht gegeven om Natura2000, een van de belangrijke instrumenten ter bescherming van de biodiversiteit in Europa, te integreren in de CL analyses voor stikstof. Het algemene doel van dit technische project was om hiertoe geografische en biodiversiteit-informatie te verzamelen van Natura2000 gebieden, en procedures te ontwikkelen om deze informatie toe te passen in de CL analyses.
De informatie over Natura2000 gebieden is verzameld en beschreven. Het betreft ruim- telijke (geografische positie) en attribuut gegevens (status, habitats, biodiversiteit, bedrei- gingen e.d.). Deze informatie is verder bewerkt, zodat verdere toepassing mogelijk is in de CL analyses voor stikstof. Deze bewerkingen omvatten het selecteren van de informatie en het combineren van informatie van de Habitat- en Vogelrichtlijn per gebied, de omzetting van de geografische codes en tenslotte de “overlay” met de EMEP50-grid.
In deze studie wordt voorgesteld om de verschillende habitats en soorten genoemd in de Habitat- en Vogelrichtlijn te integreren door de toepassing van een “habitat-benadering”.
Er is een procedure ontwikkeld waarin wordt bepaald of het noodzakelijk is om een CL analyse uit te voeren, bijv. voor een overwinteringsgebied voor vogels is een dergelijke analyse niet nodig. Deze habitat-benadering is op dit moment nog niet mogelijk voor de soorten uit de Richtlijnen, door een gebrek aan habitatgegevens voor deze soorten. De omzetting van de habitat classificatie voor de Natura2000 gebieden naar de EUNIS-habitat classificatie gebruikt in de: CL analyses wordt beschreven. Met de EUNIS habitat klassen is een koppeling mogelijk met de empirisch vastgestelde kritische drempels (eCL). Ook de noodzaak en mogelijkheden om veranderingen in biodiversiteit op te nemen in de CL analyses zijn onderzocht.
In Hoofdstuk 4 worden de verschillende stappen voor de totstandkoming van de
“critical load” kaarten voor de Natura2000 gebieden beschreven. Verschillende varianten van de eCL-kaarten voor de Natura2000 gebieden worden gepresenteerd en onderling en met een “totale” (niet-Natura2000 én Natura2000 gebieden) kaart vergeleken. Afhankelijk van de kaartvariant zijn Natura2000 gebieden gevoeliger dan niet-Natura2000 gebieden, met uitzondering van de Scandinavische en berggebieden. De resultaten zijn afhankelijk van het type habitat informatie.
Er zijn een groot aantal discussiepunten en aanbevelingen behandeld. Aan de ene kant kunnen de beschikbare gegevens van de Natura2000 gebieden en eCL verbeterd worden.
Aan de andere kant dienen de verschillende procedures voor de CL analyses en de productie van de CL kaarten verder onderzocht te worden, met name met welke habitat informatie deze kaarten gemaakt zouden moeten worden.
1. Introduction
1.1. Nature protection in Europe: Natura2000
Nature in Europe is threatened due to loss and fragmentation of habitats by more intensified land use, major infrastructures and spread of urban areas, and due to loss of habitat quality by e.g. climate change, disturbance, air pollution especially nitrogen enrichment. The European Union wants to stop the decline in biodiversity by 2010. One of the main instruments to stop this decline is the creation of an ecological network of protected sites across Europe: Natura2000. The aims of the Natura2000 network are to preserve and restore biodiversity in the European Union (LNV, 2003).
Member states were asked to select nature protection area’s based on the Bird Directive from 1979 and the Habitat Directive of 1992 (EC, 2005a). In the Bird directive (EC, 1979) all wild birds and their most important habitats across EU are protected. Based on this directive EU members have to protect the most important sites for all migratory birds and 195 threatened species, in so-called Special Protected Areas (SPA). The Habitat Directive (EC, 1992) contributes to preservation and restoration of biodiversity through the conservation of natural habitats and protection of wild fauna and flora. Member states have to propose protected area’s, so called ‘Sites of Community Interest’ (SCI) for habitats of Annex I and species from Annex II of the Habitat Directive. The European Commission evaluates the proposed sites according the rules from Annex III of this directive. After approval Member states designate the SCI as Special areas of conservation (SAC). Both the SPA and SAC together form the Natura2000 network.
1.2. Nitrogen deposition
One of the most important anthropogenic factors influencing biodiversity is nitrogen enrichment. Emissions of nitrogen, as ammonia and nitrogen oxides, have strongly increased in Europe in the second half of the 20th century. While ammonia is mainly emitted by intensive agriculture, nitrogen oxides derive mainly from burning of fossil fuels, traffic and industry (Acherman and Bobbink, 2003). Both by wet and dry deposition, these nutrients become available in the surroundings or further away from the source. The effects of nitrogen emissions on flora and fauna can be direct, via toxicity, or indirect via changes in soil properties that affect habitats for plants and animals. Nitrogen enrichment affects ecosystem via acidification of soils, an important recognized problem since the early 1980s, but also by enhanced availability of the nutrient nitrogen (eutrophication).
Acherman and Bobbink (2003) summarised the indirect effects of enhanced nitrogen loads:
• enhanced plant productivity that may result in changes in species composition in oligo- and mesotrophic habitats;
• enhanced nitrogen concentrations in plant tissue, affecting palatability of vegetation for herbivores or sensitivity to pathogens;
• increased nitrogen leaching from soils to deeper ground water when soils are saturated;
• changes in dominance of nitrogen form from nitrate to ammonium; affecting species that are sensitive to ammonium;
• acidification;
• increased susceptibility to secondary stress and disturbance factors as drought, frost, pathogens or herbivores.
The size of the effects of deposition depend on several factors, like duration and amount of increased inputs, sensitivity of organisms, abiotic conditions, land use and management (Acherman and Bobbink, 2003). For ecosystems these effects become visible via e.g.
biomass increases or shifts in species composition (Acherman and Bobbink, 2003) and may ultimately lead to changes in habitat type and structure, thereby affecting all kinds of organisms.
1.3. Calculations of critical loads for Natura2000 areas
The Coordination Centre for Effects (CCE) in Bilthoven, The Netherlands is the data centre of International Cooperative Programme (ICP) of the Long-range Transboundary Air Pollution (LTRAP). It collects and collates data of National Focal Centers (NFCs) on critical loads and related variables, applies ICP calculation methods and generates data bases available for integrated assessment models (CCE, 2007). A critical load is used as a quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to the present knowledge (Nilsson and Grennfelt, 1988). Critical loads for nitrogen can be estimated based on soil properties and steady-state mass balance methods or based on scientific knowledge on effects of nitrogen enrichment on ecosystems, so-called empirical critical loads. From the critical loads and nitrogen deposition the exceedance of the critical load can be calculated using several methods (CCE, 2007). Exceedance of critical loads for nitrogen results in nitrogen enrichment, which leads to changes in biodiversity.
Since Natura2000 areas are specifically designated to protect specific habitats, specific plants, birds and other animals, and enhanced nitrogen deposition may be a significant threat to biodiversity (Bareham et al., 2007), it is important to take the Natura2000 network into account in the critical load analysis. By integrating biodiversity and changes therein in calculations of critical loads possible exceedances of nitrogen in Natura2000 areas can be signalled more precisely.
1.4. Aim of the project The general aim of this project is:
To collect information of Natura2000 areas, both on geography and biodiversity, and develop procedures to apply and interpret this information in calculations of critical loads for nitrogen.
This general aim led to the following research objectives that are covered in the chapters of this report:
• information from Natura2000 areas was collected and described on geographical position, status, biodiversity, etc. This information was aggregated and converted to make further processing in the critical load calculations for nitrogen possible (Chapter 2);
• biodiversity information from the Natura2000 areas was evaluated (Chapter 3):
o the habitat classification of the Natura2000 areas was converted to the EUNIS classification used in critical load calculations (§ 3.2.);
o a procedure was developed to include the available biodiversity information from the Natura2000 areas into the critical load analysis (§ 3.3.);
o and the availability of data on changes in biodiversity in Natura2000 areas for critical load calculation was evaluated (§ 3.4.);
• and finally a procedure was developed to combine the information on Natura2000- areas with critical loads for nitrogen for these areas (Chapter 4).
Simultaneously with this project Expert group 4 of the European Union Project Streamlining European 2010 Biodiversity Indicators (SEBI) focused on the availability of (existing) indicators for nitrogen deposition and assessed the impact of nitrogen deposition for biodiversity. Since both projects had some cooperative aims, both projects profited from exchange of information.
2. Basic data of Natura2000
2.1. General
First the basic information from the Natura2000 areas is described (§ 2.2.). This information has been processed, so that it can be used in the critical load analysis. This includes the conversion of codes and the combining information of Habitat- and Bird- directive (§ 2.3) and eventually the overlay with the EMEP50-grid (§ 2.4.).
2.2. Description of the Natura2000 data
The Natura2000 data is stored in two files. One file which contains mostly spatial information and another file which contains most of the attribute information.
Spatial information
The spatial file is an ARC-GIS 9.X personal-geodatabase (version 15 January 2007) with polygon information per area. It has been delivered on CD officially by the European Commission to CCE in July 2007 and contains 23,105 Natura2000 areas of both directives, see Table 1. The majority, c. 81%, of the number of areas is under the Habitat directive.
Areas identified in the spatial file to be assigned to both directives comprise only less than 1%. However, this number is much higher, because from the geographical overlay of the information (see further) is became clear that though many areas are under both directives, this is not identified in the spatial file. After the overlay the areas under both directives comprises about the half of the total surface of the Natura2000 areas (data not shown).
Table 1. Number of Natura2000 areas in the official spatial database of the EU, characterized per directive type.
Type number %
Bird-directive (SPA) only: 2,807 12.1 Habitat-directive (SCI) only: 18,596 80.4
Both directives: 1,672 7.2
Unknown directive: 30 <0.3
Total 23,105 100.0
Besides the geographical information of the areas, this database also contains spatial information on geometrical variables like AREA and PERIMETER of the areas.
Other information included in the spatial file is:
- SITECODE: identification code Natura2000 areas and link to attribute file;
- SITETYPE: type of directive and in case of two directives for a specific area the extent of overlap between the directives;
- SITENAME: full name of Natura2000 area.
Attribute information
The second file, the attribute file, is a Microsoft-Access 2003 database (version 30 August 2006), which is downloaded from the website of EEA (EEA, 2007). The information in the attribute file is based on the ‘standard data form’ for Natura2000 areas (EC, 2007). The file includes information on geographical, ecological and site descriptive data and information about impacts and activities around the Natura2000 areas. Important tables are:
- BIOTOP (table with all Natura2000 areas);
- HABIT1 (table with cover (%) for each Annex I habitat in Natura2000 areas);
- HABIT2 (table with cover (%) for coarse habitat codes in Natura2000 areas).
The file contains information on 16,491 areas of both directives, see Table 2. Again the areas from the Habitat directive form the lion’s share (86%) of all areas. This file contains information on the presence of one or several habitat types for each area. These habitat types may be according to a fine or coarse classification. For the Bird directive about 60%
of the areas have a fine habitat classification, whilst this percentage is 96% for the areas of the Habitat directive. The presence of habitat information is often not for 100% of the area, and sometimes covers a small percentage (like 1%) of the total area.
Table 2. Number of Natura2000 areas in the official attribute database of the EU, characterized per directive type and presence of habitat information.
Habitat-information
Directive* fine (only) coarse (only) both none total
Bird-directive (only) 43 1570 666 182 2461
Habitat-directive (only) 275 524 11255 24 12076
Both 64 60 1826 2 1952
Total 382 2154 13747 208 16491
* Bird directive includes subtypes: A, D, F, H, J; Habitat directive include subtypes: B, E, G, I, K; both directives include subtypes: B, C, D, E, F, G, H, I, J, K.
Comparison of spatial and attribute files
There are 14,778 areas which are present in both the spatial and attribute file. So, 64% of the areas in the spatial file have information in the attribute file. And, 90% of the areas in the attribute file have information in the spatial file. Especially the twelve new or future EU-countries (so called EU10 countries and Romania and Bulgaria) have limited attribute information of Natura2000 areas, see Table 3. For Romania and Bulgaria there are even no Natura2000 areas in the files at all at this moment.
Table 3. Availability of spatial and/or attribute information of Natura2000 areas per country in the European Union.
spatial attribute both total
Country (only) (only)
EU15 countries (15 members of the EU before 2004)
Austria (AT) 3 0 210 213
Belgium (BE) 1 1 450 452
Germany (DE) 2259 1083 2841 6183
Denmark (DK) 1 11 332 344
Spain (ES) 766 6 894 1666
Finland (FI) 78 1 1779 1858
France (FR) 470 1 1204 1675
Greece (GR) 208 0 151 359
Ireland (IE) 13 80 461 554
Italy (IT) 1245 51 1279 2575
Luxembourg (LU) 0 0 59 59
Netherlands (NL) 0 0 211 211
Portugal (PT) 51 3 85 139
Sweden (SE) 13 461 3537 4011
United Kingdom (UK) 3 21 844 868
Subtotal 5111 1719 14337 21167
EU10 (12 members of the EU since 2004)
Bulgaria (BU) 0 0 0 0
Cyprus (CY) 28 0 2 30
Czech Republic (CZ) 864 0 38 902
Estonia (EE) 486 0 67 553
Hungary (HU) 457 0 55 512
Lithuania (LT) 299 1 39 339
Latvia (LV) 239 0 97 336
Maltha (MT) 27 0 6 33
Poland (PL) 175 0 72 247
Romania (RO) 0 0 0 0
Slovenia (SI) 259 0 27 286
Slovakia (SK) 382 0 38 420
Subtotal 3216 1 441 3658
Total 8327 1720 14778 24825
2.3. Conversion of spatial information of Natura2000 areas
The spatial data from the Natura2000 areas is not compatible with the data structure of de CCE-CL database: 1) there can be several records for one Natura2000 area, because areas are (partially) designated to both directives, whilst the CCE-CL database requires one record per area; 2) in the CCE-CL database a EMEP-polar projection and a EMEP50-grid is used for the geographical characterization of areas; the Natura2000 areas have a different
projection and lack the EMEP50-grid information. In the Annexes a full description of all files and queries, and a flow diagram is presented for the processing of the results.
Conversion to one record per Natura2000 area in the CCE-CL database
Areas can be designated to both the Bird directive and Habitat directive, resulting in two records per area. Furthermore there are areas without directive information in the spatial database. In order to convert the spatial data to one record per area with directive information the following procedure have been used.
First, the different directives were separated. This have been done by using the variable (SITETYPE), which describes to which directive(s) an area had been designated (Bird directive: classes A, C, D, F, H and J; and Habitat directive: classes B, C, E, G, I and K; no directives: blank value). This variable is present in both the spatial and attribute database.
The classes for the variable SITETYPE were not always the same in the spatial and attribute database, but were always indicating the same directive. We used principally the SITETYPE information from the spatial database, because the spatial database is more recent than the attribute database. However, there were 201 areas without directive information in the spatial database, but with directive information in the attribute-database.
For these cases we used the SITETYPE-information from the attribute-database. In order to identify these special cases we added a new variable to the spatial database (SITETYPE_UPDATE).
Second, an overlap was made of the polygons of the areas of the different directives, in order to create sub-areas with none, one or a combination of directives. This step was done per country, because the spatial files were too big to execute this step in once for the whole of Europe. An automated Python 2.4 procedure (COMBINE_DIRECT_LOOP.PY) was developed using ARCGIS 9.2. The following steps have been carried out per country:
- Creation of a new personal geodatabase per country, which contains the outcomes of the following actions;
- Selection of the terrestrial and freshwater areas per country by clipping, so excluding marine areas and areas outside or crossing borders. For clipping we used the European polygon shape files (European country map EUnAllAr);
- Overlay of the directive information using the UNION-function;
- Adding a new variable for determining the directive-class and calculating the directive class by means of a query: 1) Bird directive, 2) Habitat directive, 3) Both and 4) Unknown;
- Part of this Python-procedure is also to create 100 m raster map (see last paragraph of this chapter).
Geographical characterization of Natura2000 areas compatible with CCE-CL database During the former step the projection of the data was converted from latitude-longitude to the EMEP-polar projection. Further an overlay was made between the Natura2000 areas, resulting from the former step, and the EMEP50-grid. Finally, in order to use Natura2000
area information in the CCE-background database, this information was converted to a grid of 100 m x 100 m.
The overlay with the EMEP50 was carried out by using a Python 2.4 procedure (OVERLAY_DIRECT_EMEP.PY), with the following actions per country:
- Overlay of the combined directive Natura2000-areas from the former step with the EMEP50-grid using the Identity-analysis using the personal geodatabases from the former step;
- Combination (‘dissolving’) of the areas by EMEP50grid with the same directive information and calculation of these combined areas in hectares;
- Exporting of the attribute part of the spatial database to a combined personal geodatabase for the whole of Europe;
The spatial information from this step will be combined in the further CL-analysis with the EUNIS-codes and Empirical critical loads from the attribute part (see Chapter 3 and 4).
For the use of the Natura2000 information in the European critical load background database, 100 meter raster maps were created per country. This was done by former mentioned Python 2.4 procedure (COMBINE_DIRECT_LOOP.PY), with the following actions per country:
- The creation of a geodatabase and clipping, described in the former conversion step;
- Conversion of the directive-polygons files to 100 meter raster grid files in EMEP- projection;
- Raster overlay of the 100 meter grids using MapAlgebra and obtaining the earlier mentioned directive classes;
- Exporting the 100 meter raster grid maps by country in ESRI-ASCII-format;
- N.B. We chose deliberately to use the EUNIS-habitat information from the Natura2000 areas themselves, instead of extracting that information from the SEI- map, see also section 5.2 first recommendation.
3. Biodiversity in Natura2000 areas in relation to critical load analysis
3.1. General introduction
In this chapter the relation between biodiversity in Natura2000 areas and critical load analysis is worked out. In § 3.2. need and possibility to include fauna into critical load analysis is explored. In the next section (§ 3.3.) it is investigated whether and how the different Natura2000 areas and species can be included in the critical load analysis. In
§ 3.4. the conversion of the habitat classification used for Natura2000 areas to the one used in the critical load analysis is described. The following section comprises the coupling of the empirical critical loads to the converted habitat types of the Natura2000 areas. Finally, the need and possibilities to include changes in biodiversity in critical analysis is explored.
3.2. Nitrogen enrichment effects on fauna
Deposition of nitrogen may affect ecosystems via acidification and eutrophication. The various ecosystems differ in their vulnerability for nitrogen enrichment due to differences in soil properties, duration and amount of nitrogen input etc. (Acherman and Bobbink, 2003, Bareham et al., 2007). Most scientific publications on effects of enhanced nitrogen deposition have focussed on effects on vegetation (see also Chapter 1). Not only plants and vegetation types are affected by nitrogen deposition, but also fauna is directly, but mostly indirectly affected via changes in habitats of the organisms. Enhanced nitrogen deposition affects food quality, food availability and changes in environmental conditions, heterogeneity in landscape and vegetation structures needed by animals to complete their life-cycle (De Vries et al., 2006)1. Since the effects of nitrogen deposition on fauna mainly act via changes in habitats, the susceptibility of fauna for nitrogen enrichment needs to be considered via the different habitats that are needed for the different phases in their life- cycle: e.g. reproduction, staging, and wintering. Dependent of the species, these different habitats may be at different places in Europe, further away from each other or close together. Not only migratory birds, but also many other animals use different habitats during different stages of their life cycle. One example of such a species is the dragonfly Aeshna viridis, a species from Annex IV of the Habitats Directive, which occurs in Europe and western Siberia and is for reproduction restricted to aquatic vegetations with Stratiotes aloides (NVL, 2002). Adult of this species however, use semi-aquatic reed and sedge vegetations, and open areas in and edges of terrestrial forests for feeding and shelter (NVL, 2002, GG, 2007). To protect the species in e.g. a Natura2000 area, the habitats used by the species in the particular area need therefore to be considered. In conclusion, effects of enhanced nitrogen deposition on fauna mainly occur via changes in habitat. Since different species often need different habitats to complete their life cycle, it is important to consider these different habitats in assessing importance for critical load analysis and in the selection procedure for Natura2000 areas.
1 De Vries et al. (2006) describes the effects of nitrogen deposition on fauna, due to changes in food quality and micro-climate as direct effects. However, we consider these effects as indirect effects since the effects acts via changes in a.o. nutrient content in plant organic matter or plant species composition. We consider direct effects as toxicological effects through high concentrations of nitrogenous compounds, like ammonia.
These effects are most likely irrelevant at the scale of our focus and therefore not considered in this report.
3.3. When and how to apply critical load analysis in Natura2000 areas?
Since ecosystems and habitats differ in sensitivity for nitrogen enrichment, from sensitive to even quite insensitive, the question arises whether we can prioritize the different ecosystem for further critical load analysis. In Figure 1 a scheme is presented of a possible procedure to prioritize Natura2000 areas to be considered in critical load analysis for nitrogen. The procedure makes use of the data EU members have to supply in the designation of Natura2000 areas (EC, 1997). Crucial elements in the procedure in Figure 1 are the protected habitat types and the required habitats for protected species and birds. In the next paragraphs the different ‘routes’ in the scheme are explained. In addition, restrictions and complications are discussed and recommendations are put forward. Ideally for each protected habitat, bird and/or species in a specific Natura2000 area the schema should be followed, so that the appropriate combinations of critical loads could be set for a Natura2000 area.
Explanation of prioritization procedure
The European Natura2000 network comprises of Natura2000 areas that are designated by the EU members based on the Bird and Habitat Directive (abbreviated further as BD and HD, respectively). These Natura2000 areas are designated to protect 218 habitat types listed in Annex I of the HD, 887 species (and their habitats) listed in Annex II of the HD, 195 bird species from Annex I of the BD and regularly occurring migratory birds not listed in this Annex I. For each Natura2000 area the aims for protection and restoration are known in the designation documents. The procedure described below is based on the information available from the Natura2000 attribute database (see § 2.2.). The Natura2000 attribute database contains information on the present status of habitats and species in Natura2000 areas. Note that this may differ partly from the final target for protection and restoration for a particular Natura2000 area, since restoration and conservation measures are being conducted. In Figure 1 the different bases for designation from the HD and BD are referred to as: habitat protection, species protection and bird protection.
The protected habitat types (218) in Natura2000 areas (Habitat protection in Figure 1) are listed in Annex I of the Habitat Directive and full descriptions of these habitat types are available in the Interpretation manual of European Habitats (EC, 2003). The habitats in Annex I are classified according to the Palaearctic habitat classification (EC, 2003).
Empirical critical loads (abbreviated to eCL, Acherman and Bobbink, 2003) are used to assess the susceptibility of habitats to nitrogen deposition, since these eCL are based on negative effects of nitrogen enrichment on habitats and biodiversity. Acherman and Bobbink (2003) reviewed the effects of nitrogen enrichment on several, mainly sensitive, habitats based on scientific publications. These eCL for specific habitats were set at an expert workshop in Berne in 2002. The habitats for which an eCL had been determined are classified according to the EUNIS habitat classification (Davies et al., 2004). So, in order to use eCL for Natura2000 areas a conversion of the Palearctic classification to the EUNIS classification was carried out (Davies et al., 2004; see § 3.3.). In addition, information about the exact locations of the different habitat types within the Natura2000 area is not
present in the Natura2000 area documentation. This type of information could contribute to a more precise critical load analysis.
Protected species mentioned in Annex II of the Habitat Directive (Species protection Figure 1) covers organisms of different groups, except birds (Table 4). Since the effects of nitrogen enrichment on species mainly acts indirectly via changes in habitat quantity and quality (see § 3.1.), assessment of nitrogen sensitivity for Natura2000 areas designated for species protection acts via the habitats. Therefore it is important to know for which stage of their life-cycle for a specific species the Natura2000 area is designated and thereby what habitats are present or required then. In the information of the Natura2000 areas a distinction is made only between protected resident species, which are present year round, and protected migratory species for which the area could be important for either reproduction, staging of wintering. However, specific information about the habitat types used by each of these protected species is however lacking in the Natura2000 documentation. This type of information should be made available, preferably directly as EUNIS classes, so it can be used in the assessment (as described in de ‘habitat protection route’ and in § 3.3.). When habitat information is available for the protected species, again eCL can be set, like for protected habitats.
Table 4. Number of protected birds, protected habitats and protected species by the Birds Directive and Habitat Directive . In addition to the number of birds also regularly occurring migratory birds are protected in Natura2000 areas.
* Among Fishes, 4 groups of species (taxa) are mentioned as genus in the Annex II of the Habitat directive, which represent in total 22 species in EU territory (EC, 2007).
** Priority species: species which are threatened with extinction and the main natural distribution areas are within the European Community, so that the European Community has a special responsibility for conservation of these typical European species threatened with extinction (EC, 1992).
Birds Directive Annex I
EU 25 Total number
Birds 195 Habitats Directive Annex I - habitats
EU 25 Total number Priority species Habitat types 218 67 Habitats Directive Annex II - species
EU 25 Total number Priority species Mammals 51 18
Reptiles 24 7
Amphibians 24 4
Fish 82 7
Invertebrates 134 14 Animal species 315 50
Pteridophyta 19 3 Gymnosperma 1 1 Angiosperma 520 196 Bryophytes 32 4
Plant species 572 204
Total 887 254
The procedure for Natura2000 areas designated for Bird protection (Figure 1) follows the same route as for Habitat Directive Annex II species. Also for birds information is available in the Natura2000 area documentation on the habitat use: resident versus migratory. But, again information on the habitat requirements of the different species is not available from the Natura2000 attribute database. For all resident and migratory breeding birds it may be clear that it is important to evaluate habitat the susceptibility of the required habitats to nitrogen deposition. Habitat requirements for these species have to be examined and should preferably become available as EUNIS classified habitats. Again, these EUNIS habitat types can be coupled to the eCL as described in de ‘habitat protection route’ and
§ 3.3. In contrast to the species from Annex II of the HD, large numbers of bird species use specific areas that might be less nitrogen sensitive during staging and wintering. Many wintering and staging birds in the Netherlands, for example, use large open waters or large open agricultural areas. Critical load analysis for these areas has no direct priority, since these systems are either mostly eutrophic (and thereby less sensitive to nitrogen enrichment), or often heavily influenced by agricultural nitrogen enrichment by fertilization and manuring. The possible exclusion of these staging or wintering species or areas across Europe should be studied in further detail. In addition, breeding birds from agricultural areas in general are also probably not influenced by nitrogen enrichment too, since nitrogen enrichment via deposition can be assumed to be negligible compared to agricultural input.
However, if this applies for all birds from agricultural areas in Europe needs further study.
In absence of the essential information on habitat requirements for birds and species and of any eCL information of Annex I habitats, the general habitat description (see Figure 1) present in the Natura2000 area documentation may give information on susceptibility for nitrogen enrichment. The general habitats distinguished in the Natura2000 attribute database are listed in Table 5. These general habitat types were converted to the first and second level EUNIS classifications (Davies et al., 2004). These EUNIS classes cover different habitats, sometimes including large ranges of nutrient availability (from oligotrophic to eutrophic) and thereby large ranges in sensitivity to nitrogen deposition.
From the general habitat descriptions it is unclear which of the more specific habitat types within the EUNIS class is present in a specific Natura2000 area. To assess sensitivity to nitrogen deposition the EUNIS-converted general description should be coupled to the eCL. In some cases different eCL ranges are available for different subclasses within the first and second level EUNIS class and in many cases eCL data are simply lacking. In Table 5 three eCL values were added to the general habitat descriptions: the minimum eCL of all known eCL-ranges at the first level EUNIS class and the median of the minimum or of the averages or the eCL-ranges within a particular EUNIS class. Application of the minimum eCL for a specific EUNIS class will protect both sensitive and less sensitive habitats, however it is clearly an overestimation of the sensitivity of the Natura2000 area.
An alternative is the application of one of the median eCL, however then sensitive habitat types within the general descriptions may be missing. The NFC may have more detailed information and may use models to determine the eCL in greater detail. We stress that the use of these general habitat classes is only indicative for nitrogen sensitivity, and used only where specific habitat information is lacking. In addition, ideally, detailed information is needed for each species in order to assess the impact of nitrogen deposition on the species.
Figure 1. Procedure to prioritize Natura2000 areas sensitive for nitrogen enrichment and relevant for critical load analysis. For each of the protected habitats, bird or species in a specific Natura2000 area the scheme should be followed. Coupling of the known eCLs from Acherman and Bobbink (2003) to the habitat types in a Natura2000 area will lead to a set of eCLs that can be used for critical load analysis. In absence of information on habitats for species, the general habitat classes (dashed line) may give indications for priorization of the Natura2000 area for critical load analysis.
See text for full details.
Natura2000 area
designated via:
High priority for CL calculations
Habitat protection ? Species protection ?
yes
Low priority for CL calculations What habitat types are therefore required ?
Is (one or more of) the habitat type(s) sensitive to nitrogen ?
no Habitat Directive ?
Bird Directive ?
Indication via general habitat description
How is de natura2000 area used by the protected species/bird(s)?
i.e. resident, breeding, wintering, staging area Bird Protection
Table 5. Overview of general habitat classes used in the description of Natura2000 areas and translation to EUNIS classes. See text for explanation of the derivation of these eCL; + = not available, but relevant, - = not available, but also not relevant for eCL-analysis.
General habitat class
General habitat description EUNIS
class Minimum
eCL Median eCL (average)
Median eCL (minimum)
N01 Marine areas, Sea inlets A + + +
N02 Tidal rivers, Estuaries, Mud flats, Sand flats, Lagoons
(including saltwork basins) A/X0/? + + +
N03 Salt marshes, Salt pastures, Salt steppes A2.5/D6/E6 30 35 30 N04 Coastal sand dunes, Sand beaches, Machair B 10 15 10
N05 Shingle, Sea cliffs, Islets B 10 15 10
N06 Inland water bodies (Standing water, Running water) C 5 11 8 N07 Bogs, Marshes, Water fringed vegetation, Fens D 5 18 13 N08 Heath, Scrub, Maquis and Garrigue, Phygrana F 5 12.5 7.5
N09 Dry grassland, Steppes E1 10 15 10
N10 Humid grassland, Mesophile grassland E2/E3 10 17.5 12.5 N11 Alpine and sub-Alpine grassland E4 5 12.5 10 N12 Extensive cereal cultures (including Rotation cultures
with regular fallowing)
I - - -
N13 Ricefields I - - -
N14 Improved grassland E2.6 - - -
N15 Other arable land I - - -
N16 Broad-leaved deciduous woodland G1 10 15 10
N17 Coniferous woodland G3 10 15 10
N18 Evergreen woodland G2 + + +
N19 Mixed woodland G4 10 15 10
N20 Artificial forest monoculture (e.g. Plantations of
poplar or Exotic trees) G5 + + +
N21 Non-forest areas cultivated with woody plants
(including Orchards, Vineyards, Dehesas etc.) G2/E7/FB + + + N22 Inland rocks, Screes, Sands, Permanent Snow and ice H - - - N23 Other land (including Towns, Villages, Roads, Waste
places, Mines, Industrial sites) J - - -
N24 Marine and coastal habitats (general)* A/B 10 15 10 N25 Grassland and scrub habitats (general)* E/F 5 15 10
N26 Woodland habitats (general)* G 10 15 10
N27 Agricultural habitats (general)* I - - -
*not mentioned in standard data form
Other useful information from Natura2000 area documentation for prioritization
The Natura2000 area documentation also contains information about relevant and threatening ‘impacts and activities’ in and around the Natura2000 areas, which could also be possibly used in the prioritization procedure. These ‘impacts and activities’ relate to all human activities and natural processes that may have an influence (positive or negative) on the conservation and management of the site (EC, 1997). Not only impacts within the Natura2000 area, but also impacts from the surroundings area that may affect the integrity of the Natura2000 site are reported. Both in- and outside impacts are of importance for the protection of the Natura2000 area. The impacts are grouped under agricultural -,, fishing - and mining activities, urbanisation, transportation, leisure, pollution, human induced changes in wet areas and natural processes. This information includes the size of intensity (high – medium – low), the percentage of the area under influence and the direction of the impacts (positive – neutral – negative). For the prioritization procedure the impact-
categories ‘eutrophication’ and ‘air pollution’ are of importance. From some other impacts the description (like the presence of highways) is too general to take this information into account, though it might be relevant. More detailed information on these possibly relevant categories is required (e.g. route of highways). When the impact of ‘eutrophication’ and
‘air pollution’ is assessed as ‘negative’, both within a Natura2000 area or in its surroundings, the Natura2000 area may be threatened by nitrogen enrichtment. Therefore, the areas threatened by these impacts should ideally be considered in critical load analysis.
In summary, a procedure was described to include Natura2000 areas in eCL analyses. One major point of discussion is how to deal with ‘insensitive’ areas (such as wintering grounds for geese) in the critical load analysis: by excluding or by applying a high critical load. Due to lack of information about habitat requirements of species (Annex IV Habitat directive and Bird directive) we propose use all available information on a detailed level (Habitats Annex I Habitat directive) and a coarse level (Habitat and Bird directive) in critical load analysis.
3.4. Conversion from Palearctic to EUNIS habitat types
The habitats in Natura2000 areas are described in the Interpretation manual of European Union habitats (EC 2003). The classification of habitats for Natura2000 had originally been based on the CORINE classification. With entrance of new member states in the EU, this CORINE classification was considered insufficient and had been updated with the PHYSIS database, which uses a Palaearctic classification of habitat types (EC, 2003). These Palaearctic classification (latest version ’97) forms the basis for the codes in the Interpretation manual of European Union habitats.
For the critical load calculations the European Nature Information System habitat classification (EUNIS) is being used (Davies et al., 2004). The EUNIS classification describes a hierarchical typology of the habitats in Europe and its adjoining seas.
From the EUNIS website a conversion table was obtained for habitat types mentioned in Annex I of the Habitat Directive to the EUNIS habitat classification (Moss and Davies, 2002; EUNIS, 2007). So this concerns only the fine and not the coarse habitat types. The Annex I habitats types are converted to a third, or more detailed, EUNIS level.
Additional information is provided on the relationships between both classifications: 1) overlap between both descriptions, 2) whether the description of the Annex I habitat is narrower, broader or identical than the EUNIS habitat. Often several EUNIS habitats are mentioned for one Annex I habitat type. In most of these cases there are subgroups at the detailed level within one EUNIS level, however, in some other cases different EUNIS- classes at the first or second level relates to a Annex I habitat type. As described in the former section, information about the habitats required by birds and other species are currently unavailable. If this kind of habitat information would become available, it should be preferably become available as EUNIS-classes, to prevent conversion problems as described above.
Table 6. Overview of the available empirical critical loads. The eCL are set in Acherman and Bobbink (2003) and additional eCL are derived for some EUNIS classes by De Bakker et al., 2007). B2003: Acherman and Bobbink (2003); dB2007: De Bakker et al,. 2007.
EUNIS code Short habitat description eCL(kg/ha/yr) Remarks Source A2.54 & A2.64 Pioneer and low-mid salt marshes 30-40 B2003
B1.3 Shifting dunes 10-20 B2003
B1.4 Coastal stable dune grasslands 10-20 B2003
B1.5 Coastal dune heaths 10-20 B2003
B1.8 Moist to wet dune slacks 10-25 B2003
C1.1 Permanent oligotrofic waters – softwater lakes 5-10 B2003 C1.16 Permanent oligotrofic waters – dune slack pools 10-20 B2003
D1 Raised and blanket bogs 5-10 B2003
D2.1 Quaking fens and transition mires 10-15 footnote in B2003 B2003
D2.2 Poor fens 10-20 B2003
D2.3 Valley mires 15-20 footnote in B2003 B2003
D4.1 Rich fens 15-35 B2003
D4.2 Mountain rich fens 15-35 B2003
E1 Dry grasslands 15-25 dB2007
E1.26 Sub-atlantic semi-dry calcareaous grasslands 15-25 B2003 E1.7 Non-mediterranean dry acid and neutral closed
grasslands 10-20 B2003
E1.8 & E1.A Mediterranean dry acid and neutral closed/open
grassland 15-20 dB2007
E1.9 Non-Mediterranean dry acid and neutral open grassland, including inland dune grassland
10-20 Adopted E1.94 & E1.95
E1.94 Inland dune pioneer grassland 10-20 B2003
E1.95 Inland dune siliceaous grasslands 10-20 B2003
E2.1 Permanent mesotrophic pastures and aftermath- grazed meadows
20-30 dB2007
E2.2 Low and medium altitude hay meadows 20-30 B2003
E2.3 Mountain hay meadows 10-20 B2003
E3.5 Moist and wet oligotrophic grasslands 10-20 Adopted from E3.52 E3.51 Moist and wet oligotrophic grasslands – Molinea
aerulea meadows 15-25 B2003
E3.52 Moist and wet oligotrophic grasslands – Heath (Juncus) meadows and humid (Nardus stricta) swards
10-20 B2003
E4.2 Moss and lichen dominated mountain summits 5-10 B2003 E4.3 & E4.4 Alpine and subalpine grasslands 10-15 B2003
F1 Tundra 5-10 B2003
F2 Acrtic, alpine ans subalpine scrub habitats 5-15 B2003 F4.11 Northern wet heaths ‘U’ Calluna dominated wet
heath 10-20 B2003
F4.11 Northern wet heaths ‘L’ Erica tetralix dominated wet
heaths 10-25 B2003
F4.2 Dry heaths 10-20 B2003
G Forest habitats 10-20 eCL depends on process B2003
3.5. Coupling of empirical critical loads to Natura2000 areas
Coupling of empirical critical loads (eCL) to Natura2000 areas is possible by using the EUNIS-classes after conversion from the Palearctic to the EUNIS habitat classification (see former section). Acherman and Bobbink (2003) have set eCL for several EUNIS classes of habitats. Based on this study we derived in a parallel project additional eCL for some other EUNIS habitats classes used in the critical load analysis (De Bakker et al., 2007), see Table 6. From this table it is clear that for quite a number of EUNIS habitat types eCL are missing. The EUNIS classes of Natura2000 areas are often known at a more detailed EUNIS level than the EUNIS habitats for which an eCL is known or derived. Therefore, an available eCL for a EUNIS class has to be applied to this EUNIS class and all (more detailed) subgroups of this EUNIS class. For example, when an eCL is available for F1 all more detailed subgroups of the EUNIS class F1 get the same eCL. Since Annex I habitats may be converted to multiple EUNIS classes, coupling to the available eCL may lead to different eCL for one Annex I habitat type. For 132 Annex I habitats an eCL could be derived and from these only 5 habitat types have two eCL. For 85 Annex I habitat types no eCL information was available. For some of these 85 Annex I habitats no eCL information is necessary since these habitats, as e.g. caves, are probably unsusceptible to nitrogen enrichment. It is clear that for many EUNIS habitats eCL information is lacking. New eCL information should be derived with priority for the protected habitats for which eCL information is lacking at the moment.
3.6. Changes in biodiversity in Natura2000 areas
Changes in biodiversity in Natura2000 areas are important for several reasons. First, the results of the critical load analysis should support the restoration of degraded Natura2000 areas. Second, information on changes in biodiversity in Natura2000 areas could be combined with changes in exceedances of critical loads, in this way the critical load analysis is supported and validated by the biodiversity information.
The aim of the Natura2000 network is to protect and restore biodiversity in the European Union (LNV, 2003). Specific aims for protection of habitats, birds and other species for the specific Natura2000 areas are part of this designation. These aims have not been reached in all Natura2000 areas. However, the biodiversity information about Natura2000 areas do not include the desired habitats, but the present (possibly degraded) habitat types and (lower) population sizes of species. To reach the aims for e.g. restoration of specific habitats conservation measures have to be taken. This may lead to changes in habitat types (e.g. from degraded to restored), altered species abundances and changed biodiversity. Note that a recovered habitat may be classified as a different habitat type than the present. This may result in a different, probably lower, eCL too, since the recovered habitat may be more sensitive to nitrogen enrichment. Also the presence of new (desired) protected species may result in specific habitat requirements that have other eCL. Ideally, the desired, restored habitats, and the desired birds and species should be considered in critical load analysis. Then the eCL will not change during e.g. the restoration of a habitat and this eCL warrants the possibility to recover. However, the information on the desired habitats and species (abundances) is only qualitative available in the Natura2000
designation documents, but not available in the Natura2000 database, so it cannot be used in critical load analysis.
Many organisations collect and publish information on changes in biodiversity in Natura2000 areas. At the national level, non-governmental organizations gather, analyze and publish information on species presence and abundance in Natura2000 areas. E.g. in the Netherlands, members of the VOFF (Vereniging Onderzoek Flora en Fauna) collect information on different groups of species. One of the members of the VOFF, SOVON, collects information on birds in The Netherlands and specifically in Natura2000 areas and publishes these data in reports. In each country such information will be probably present, though these data cover many different studies, probably often reported in the national language, etc. Therefore, application of this kind of information in critical load analysis on the European scale needs a lot of efforts, to sample, translate and convert to database formats. However, these monitoring data may be part of the information EU members have to report on the status of the Natura2000 areas to the European Union.
EU members have to report each 6 years on the conservation measures and the effects thereof on the protected habitats, protected species and birds according Article 17 of the Habitat Directive. This information should be collected and reported according a standard format (Format for the next status report, period 2000-2007, see EC, 2007). The EEA is developing an electronic application for this reporting (EEA, 2007). If and how this information is joined to the Natura2000 database information is yet unknown. To date, it is also uncertain whether this type of information will be freely accessible (J. Thissen, LNV, personal comment). NFC may have access to the monitoring information for the Natura2000 areas. From the information of the EU members, the EU commission will evaluate the status and trends of biodiversity in relation to the measures per biogeographical region in Europe (EC, 2005b; EC, 2006).
Besides the information on the national and European scale, scientific publications may yield information about biodiversity across Europe. This information is, however often not at the level of individual Natura2000 areas and gives overviews on biodiversity trends in Europe or in a particular country.
In summary, electronic information on changes of biodiversity in Natura2000 areas will probably become available in the forthcoming years, which might be used to support the critical load analysis.
4. Production of eCL-maps for Natura2000 areas
4.1. General
In this chapter eCL maps have been produced for Natura2000 areas on basis of the basic information of the Natura2000 areas (Chapter 2) on the one hand and procedures and eCL information for the Natura2000 areas (Chapter 3) on the other hand. In the first section the different steps to adapt the available eCL- and habitat-information for the production of eCL-maps are described. In the final section the production of the eCL maps for Natura2000 areas is described and several eCL-maps are presented. In the Annexes a full description of all files and queries, and a flow diagram is presented for the processing of the results.
4.2. Handling of habitat information and assignment of eCL for Natura2000 areas The habitat information of the Natura2000 areas is the key information for the assignment of eCL to Natura2000 areas, as described in Chapter 3. The Natura2000 habitat codes have to be converted to EUNIS-habitat codes to make linkage with eCL possible. In this section the different adaptation steps are described.
For these steps the following input tables have been used:
- BIOTOP (table with all Natura2000 areas);
- HABIT1 (table with cover (%) for each Annex I habitat in Natura2000 areas);
- HABIT2 (table with cover (%) for coarse habitat codes in Natura2000 areas).
These three input tables are part of the attribute database, see Chapter 2.
- Table 5 and 6, which are the result of the adaptation of the eCL-information in Chapter 3.4.
The following aspects of habitat and eCL-information have been taken into account:
1. in the conversion from Natura2000 habitat codes to EUNIS habitat codes different types of relationships between these codes have to be accounted for;
2. some coarse Natura2000 habitat classes have been converted to combinations of EUNIS-classes;
3. for some areas Natura2000 habitat codes are used, that are not mentioned in Annex I of the Habitat directive;
4. for some areas information about surface is missing for some habitats;
5. for some areas the sum of the cover for all habitats within one area is less or more than 100%;
6. habitat information is present at a fine (Annex I) and/or coarse level (see Chapter 3), so this information have to be combined if necessary and possible.
Ad 1) As described in section 3.4. the conversion of Natura2000 habitat codes to EUNIS habitat codes, several types of relationships can be distinguished between the types of codes, see Table 7. One Natura2000 habitat code can be converted to several EUNIS habitat codes at different levels with different relationships.
